Clogging often affects the effective functioning and may even causes the failure of leachate collection systems for municipal solid waste landfills.The precipitation of calcium carbonate that is induced by fermentation of volatile fatty acids(VFAs)is a primary cause of clogging.This paper presents a geochemical model for predicting the amount of calcium carbonate precipitation.By simulating two series of laboratory column experiments,this model is verified,and the relationship between calcium carbonate precipitation and VFAs fermentation is revealed.